Method for producing fine structured member, method for producing fine hollow structured member and method for producing liquid discharge head

Abstract

The invention is to provide a method for producing a fine structured member and a fine hollow structure, useful for producing a liquid discharge head which is inexpensive, precise and highly reliable, also to provide a method for producing a liquid discharge head utilizing such producing method for the fine structured member and the fine hollow structure and a liquid discharge head obtained by such producing method. A positive-working photosensitive material, including a ternary polymer containing an acrylate ester as a principal component, acrylic acid for thermal crosslinking and a monomer unit for expanding a sensitivity region, is used as a material for forming the Line structured member.

What is claimed is: 
     
       1. A method for producing a fine hollow structured member on a substrate comprising:
 a step of forming a positive-working photosensitive material layer on a substrate; 
 a step of heating said positive-working photosensitive material layer thereby crosslinking said positive-working photosensitive material layer; 
 a step of executing an irradiation with an ionizing radiation of a first wavelength region capable of decomposing said crosslinked positive-working photosensitive material layer on a predetermined area of said crosslinked positive-working photosensitive material layer; and 
 a step of removing, by a development, the area irradiated by the ionizing radiation of said crosslinked positive-working photosensitive material layer from the substrate, thereby obtaining a mold pattern formed by a non-irradiated area by the ionizing radiation of said crosslinked positive-working photosensitive material layer; 
 a step of forming a covering resin layer, formed by a negative-working photosensitive material sensitive to a second wavelength region, in a position covering at least a part of the mold pattern on said substrate; 
 a step of irradiating said covering resin layer with an ionizing radiation of the second wavelength region thereby hardening said covering resin layer; and 
 a step of removing, by dissolution, the mold pattern covered by said hardened covering resin layer from the substrate thereby obtaining a hollow structure corresponding to said mold pattern; 
 wherein said positive-working photosensitive material layer includes a ternary copolymer containing methyl methacrylate as a main component, methacrylic acid as a thermally crosslinkable factor and a factor for expanding a sensitivity region for said ionizing radiation; and 
 said first wavelength region and said second wavelength region do not overlap mutually. 
 
     
     
       2. A method for producing a fine hollow structured member according to  claim 1 , wherein the crosslinking by said heat treatment is caused by a dehydration condensation reaction. 
     
     
       3. A method for producing a fine hollow structured member according to  claim 1 , wherein said factor for expanding the sensitivity region is methacrylic anhydride. 
     
     
       4. A method for producing a fine hollow structured member according to  claim 3 , wherein said ternary copolymer includes methacrylic acid in a proportion of 2 to 30 wt. % with respect to said copolymer, and is prepared by a radical polymerization of cyclized polymerization type at a temperature of 100 to 120° C. employing an azo compound or a peroxide as a polymerization initiator. 
     
     
       5. A method for producing a fine hollow structured member according to  claim 3 , wherein said ternary copolymer has a weight-averaged molecular weight within a range from 5,000 to 50,000. 
     
     
       6. A method for producing a fine hollow structured member according to  claim 1 , wherein said factor for expanding the sensitivity region is glycidyl methacrylate represented by a following formula: 
       
         
           
           
               
               
           
         
       
     
     
       7. A method for producing a fine hollow structured member according to  claim 6 , wherein said ternary copolymer includes methacrylic acid in a proportion of 2 to 30 wt. % with respect to said copolymer, and is prepared by a radical polymerization at a temperature of 60 to 80° C. employing an azo compound or a peroxide as a polymerization initiator. 
     
     
       8. A method for producing a fine hollow structured member according to  claim 6 , wherein said ternary copolymer has a weight-averaged molecular weight within a range from 5,000 to 50,000. 
     
     
       9. A method for producing a fine hollow structured member according to  claim 1 , wherein said factor for expanding the sensitivity region is methyl 3-oxyimino-2-butanone methacrylate represented by a following formula: 
       
         
           
           
               
               
           
         
       
     
     
       10. A method for producing a fine hollow structured member according to  claim 9 , wherein said ternary copolymer includes methacrylic acid in a proportion of 2 to 30 wt. % with respect to said copolymer, and is prepared by a radical polymerization at a temperature of 60 to 80° C. employing an azo compound or a peroxide as a polymerization initiator. 
     
     
       11. A method for producing a fine hollow structured member according to  claim 9 , wherein said ternary copolymer has a weight-averaged molecular weight within a range from 5,000 to 50,000. 
     
     
       12. A method for producing a fine hollow structured member according to  claim 1 , wherein said factor for expanding the sensitivity region is methacrylonitrile represented by a following formula: 
       
         
           
           
               
               
           
         
       
     
     
       13. A method for producing a fine hollow structured member according to  claim 12 , wherein said ternary copolymer includes methacrylic acid in a proportion of 2 to 30 wt. % with respect to said copolymer, and is prepared by a radical polymerization at a temperature of 60 to 80° C. employing an azo compound or a peroxide as a polymerization initiator. 
     
     
       14. A method for producing a fine hollow structured member according to  claim 12 , wherein said ternary copolymer has a weight-averaged molecular weight within a range from 5,000 to 50,000. 
     
     
       15. A method for producing a fine hollow structured member according to  claim 1 , wherein said factor for expanding the sensitivity region is fumaric anhydride represented by a following formula: 
       
         
           
           
               
               
           
         
       
     
     
       16. A method for producing a fine hollow structured member according to  claim 15 , wherein said ternary copolymer includes methacrylic acid in a proportion of 2 to 30 wt. % with respect to said copolymer, and is prepared by a radical polymerization at a temperature of 60 to 8° C. employing an azo compound or a peroxide as a polymerization initiator. 
     
     
       17. A method for producing a fine hollow structured member according to  claim 15 , wherein said ternary copolymer has a weight-averaged molecular weight within a range from 5,000 to 50,000. 
     
     
       18. A method for producing a fine hollow structured member according to  claim 1 , wherein a positive-working photosensitive material includes a photodegradable resin having at least a carboxylic acid anhydride structure. 
     
     
       19. A method for producing a fine hollow structured member according to  claim 18 , wherein the positive-working photosensitive material is an acrylic resin which is subjected to an intermolecular crosslinking through the carboxylic acid anhydride structure. 
     
     
       20. A method for producing a fine hollow structured member according to  claim 19 , wherein the positive-working photosensitive material is an acrylic resin having an unsaturated bonding in a side chain. 
     
     
       21. A method for producing a fine hollow structured member according to  claim 19 , wherein the positive-working photosensitive material includes a structural unit represented by following general formulas 1 and 2: 
       
         
           
           
               
               
           
         
       
       wherein R 1  to R 4 , which may be mutually same or different, each represents a hydrogen atom or an alkyl group with 1 to 3 carbon atoms. 
     
     
       22. A method for producing a fine hollow structured member according to  claim 21 , wherein the first positive-working photosensitive material includes a structural unit represented by a following general formula 3: 
       
         
           
           
               
               
           
         
       
       wherein R 5  represents a hydrogen atom or an alkyl group with 1 to 3 carbon atoms. 
     
     
       23. A method for producing a fine hollow structured member according to  claim 1 , wherein the first wavelength region is of a shorter wavelength than the second wavelength region. 
     
     
       24. A method for producing a fine hollow structured member according to  claim 1 , wherein said negative-working photosensitive material includes an epoxy resin as a principal component. 
     
     
       25. A method for producing a liquid discharge head comprising steps of forming a mold pattern with a removable resin in a portion where a liquid flow path is to be formed on a substrate on which a liquid discharge energy generating element is formed; coating and hardening a covering resin layer on said substrate so as to cover said mold pattern; and removing by dissolution said mold pattern thereby forming a liquid flow path having a hollow structure;
 wherein said liquid flow path is formed by a method for producing a fine hollow structure according to  claim 1 . 
 
     
     
       26. A method for producing a liquid discharge head according to  claim 25 , wherein a developing liquid containing at least:
 1) a glycol ether having 6 or more carbon atoms and miscible with water in an arbitrary ratio; 
 2) a nitrogen-containing basic organic solvent; and 
 3) water is used for developing said mold pattern. 
 
     
     
       27. A method for producing a liquid discharge head according to  claim 26 , wherein said glycol ether is ethylene glycol monobutyl ether and/or diethylene glycol monobutyl ether. 
     
     
       28. A method for producing a liquid discharge head according to  claim 27 , wherein said nitrogen-containing solvent is ethanolamine and/or morpholine.